Passive MEMS Tagging of Personnel (PMTP)

"RSI, in collaboration with the Applied Physics group of Princeton University, proposes to utilize MEMS electroforming techniques to produce a passive micro-machined metal corner cube retro-reflector on the 20--100 micron size scale. As a Passive MEMS Tagfor Personnel (PMTP), such a all-metal retroreflector would be outfitted with an optically absorbing thin filter. The tags, when interrogated optically, would retroreflect with different intensities at two different wavelengths, providing a simple encodingscheme. The intensity ratio would be varied in each production batch by altering the deposition thickness of the filter coating. The six month base Phase I program will produce a single size prototypical tag with a set of three different filterthicknesses. Exercising the optional extra three month program would support an additional range of sizes of PMTPs. By the end of the program, 1) optical filter tags will be designed and validated; 2) a prototype microscopic retroreflector will bedesigned, 3) fabricated, 4) examined to ascertain the success of fabrication and 5) PMTP tags will be characterized to determine the optical properties of such a microscale retroreflector. The fight against insurgent groups who coalesce for a campaign andthen scatter upon conclusion could be greatly aided by the PMTP personnel tag, which can be applied covertly and survive undetected for an extended period of time. The PMTP tag is interrogated optically, out of the perceptual range of adversaries, andpotentially from a wide range of distances. The ability to encode information as to what batch of PMTP tags a suspect is unwittingly wearing may also give important intelligence as to enemy troop movements and aid in interrogation. The usefulness of amicrofabricated optically interrogated tag would not end with the tagging of enemy personnel. Friendly forces, suspected double-agents, and non-combatant civilians, criminal suspects, documents, materiel, and vehicles could similarly be tagged and labelledusing microscale tags. Commercial markets include law enfor